In related techniques, it is known to superimpose a character, an image, or the like, on another image at a particular position and transmit a resultant image signal. An example of such a technique is known as an on screen display function (hereinafter, referred to as an OSD function) to display information such as a character, an image, or the like, on another image at a fixed position.
It is also known to dynamically change the position at which information such as a character, an image, or the like, is superimposed. For example, PTL 1 discloses an image pickup apparatus configured such that when a housing of a camera is panned or tilted, the position of a cursor on a display screen is moved in response to the movement of the housing.
In the OSD function in the related technique, various superimposing methods are known. One method is to specify an encoder in performing superimposing for an image source. Another method is to allow a user to specify a received stream to be subjected to superimposing.
For example, in the case where superimposing is performed on an image source, the OSD function is applied such that superimposing is performed on all images transmitted from an image pickup apparatus. On the other hand, in the case where superimposing is performed on a stream to be transmitted, only a user who receives the stream is allowed to view the superimposed information such as a character or an image.
In a situation in which a plurality of superimposing methods are supported, there is a need for a technique to select one of the superimposing methods depending on a user or an application.
However, in setting OSD functions according to related techniques, it is not allowed select a superimposing method from a plurality of methods.
Among the plurality of superimposing methods, in the method of specifying an encoder used in the superimposing, a difference may occur in terms of a scope of information to be subjected to superimposing depending on whether the information is superimposed on a picked-up image before the picked-up image is encoded, or after the picked-up image is encoded.
That is, in the case where a character, an image, or the like is superimposed on a picked-up image before the picked-up image is encoded, it is easy to display the same character, image, or the like, on all picked-up images to be subjected to the same encoding. On the other hand, in the case where a character, an image, or the like, is superimposed on a picked-up image after the picked-up image is encoded, the character, the image, or the like, is displayed only on the picked-up image applied with particular setting.
In most cases, the setting of the encoding method includes setting of an image size or an image resolution. That is, when the encoding method is set, the image size of an image to be encoded is set, and enlarging or reducing of a picked-up image is performed before the encoding process. The process of enlarging/reducing the picked-up image includes sampling the image, interpolation, and the like.
In the case where an encoder is specified in the superimposing, there is a possibility that a difference may occur in terms of a range of information such as a character or an image to be subjected to superimposing depending on whether the superimposing is performed before or after the process of enlarging/reducing the picked-up image is performed.
As described above, in the superimposing method in which the encoder is specified, the scope subjected to the superimposing may vary. A user may be allowed to set all items such that such a difference does not occur. However, in this case, the user has to perform a troublesome operation, which results in a reduction in convenience for users.